The Mesozoic hemipteran family Archijassidae, known from the Late Triassic to the Early Cretaceous, is recorded as the ancestral group of mega-diverse leaf- and treehoppers. On the basis of a fossil contained in Kachin amber from the lowermost Upper Cretaceous of northern Myanmar, we herein erect a remarkably new taxon, Formosixinia aeterna Chen & Wang, gen. et sp. nov. The new genus and species can be assigned to Archijassidae based upon a series of body and wing characteristics, but also displays some unique traits, making it distinctly different from all known archijassids and even quite unique within Cicadelloidea. Our finding not only reveals the youngest record of Archijassidae but also the first representative of this family in amber, and it further provides some novel information on the morphological disparity and evolutionary history of early leafhoppers. (C) 2019 Elsevier Ltd. All rights reserved.